Re: 32-bit kernel on PPC64 supported?
Hi, On Saturday 19 July 2008 00:14:35 Benjamin Herrenschmidt wrote: On Fri, 2008-07-18 at 20:43 +0200, Marvin wrote: Hi, while trying to cleanup some configs/makefiles for ppc64 I noticed, that CONFIG_POWER4 implies CONFIG_PPC64 and vice versa in all defconfigs. So I want to boldly replace CONFIG_POWER4 by CONFIG_PPC64 - ugh. No, those are different. CONFIG_PPC64 means a 64 bits kernel. CONFIG_POWER4 means a 64 bits kernel that only runs on IBM POWER4 and later (ie, processors conforming to, iirc, version 2.01 or later of the architecture). That is, it's legal to have CONFIG_PPC64 and !CONFIG_POWER4, and this is even necessary if you want to boot on a POWER3 or an RS64 processor. I don't want to replace CONFIG_POWER4 by void, but by something like CONFIG_TUNE_POWER4 (see my previous post, one week ago). So there is no feature loss. CONFIG_POWER3 is used only to define HAVE_BATS, so I thought I can clean this up. Now, there also used to be some 32 bits support for POWER4 and G5 but that has been dropped a while ago. Ok - that's fine. I hope to finish my patches during the weekend, so things will become more clear. Greetings Marvin ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: 32-bit kernel on PPC64 supported?
On Friday 18 July 2008, Marvin wrote: in which POWER4 is always undefined, e.g. in include/asm-powerpc/mmu_context.h. Maybe this is a leftover from times, where 64-bit kernels where not supported on Powermacs. Is this 32-bit support still necessary? There is currently no 64-bit machine that is supported by current kernels, and I don't think there is any reason to add this again. I'm not sure what the point of your plan to replace CONFIG_POWER4 is, but it sounds like this case is slightly different, as you remove a potential feature, so I guess it should be a separate patch. Arnd ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
Re: 32-bit kernel on PPC64 supported?
On Fri, 2008-07-18 at 20:43 +0200, Marvin wrote: Hi, while trying to cleanup some configs/makefiles for ppc64 I noticed, that CONFIG_POWER4 implies CONFIG_PPC64 and vice versa in all defconfigs. So I want to boldly replace CONFIG_POWER4 by CONFIG_PPC64 - ugh. No, those are different. CONFIG_PPC64 means a 64 bits kernel. CONFIG_POWER4 means a 64 bits kernel that only runs on IBM POWER4 and later (ie, processors conforming to, iirc, version 2.01 or later of the architecture). That is, it's legal to have CONFIG_PPC64 and !CONFIG_POWER4, and this is even necessary if you want to boot on a POWER3 or an RS64 processor. Now, there also used to be some 32 bits support for POWER4 and G5 but that has been dropped a while ago. Cheers, Ben. ___ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
